Tom Kontogiannis

User strategies in recovering from errors in man–machine systems

Abstract Safety science has long been dominated by the concept of error suppression or prevention. With the increasing complexity of man–machine systems, however, error recovery may seem an important supplementary safety goal since total error prevention may be difficult to achieve. This article presents an elaborate examination of the different processes of error recovery (i.e. detection, explanation, correction), the stages at which they might occur, and the types of recovery goals that users may set themselves. A research framework is proposed on the basis of a taxonomy of user strategies which could support error recovery. User strategies can range from information search strategies (i.e. inner feedback, system error cueing, communications) to planning behaviours and learning from errors. The research framework explores how error detection and correction may vary as a function of error types, recovery stages, and user strategies. The benefits of this framework are illustrated in the context of system design and training regimes which can enhance recovery from errors.

Stress and operator decision making in coping with emergencies

Abstract Although considerable effort has been put into the design of hardware-oriented strategies for mitigating high risk emergencies, the role of decision aids and training strategies to support human performance under stress has not been explored systematically. This has important implications for the management of emergencies since inadequacies in decision-making skills may jeopardise the success of any hardware-oriented mitigations. This paper proposes a quasi-analytical framework of decision making under stress to integrate findings of the stress literature and identify cognitive activities and skills involved in decision making. Practical implications of the proposed framework include; designing simulations of system emergencies, monitoring and analysing operator performance under stress, and providing guide- lines for making training hypotheses about instructional strategies which could potentially lead to improved performance. A case study from the nuclear industry is also presented to illustrate the theoretical framework and the proposed tools.

Stress and team performance: principles and challenges for intelligent decision aids

Advances in computer technology and artificial intelligence are providing powerful capabilities for developing intelligent decision aids (IDAs) to support operating teams in managing complex systems. Early system designs, which acted as independent computer advisors, constrained human decision making, were brittle and encountered problems of user acceptance. As a result, there has been a shift towards making IDAs more cooperative in assisting users to make decisions under stress. Although there is a growing body of research on how to design IDAs as collaborate team players, this article provides additional insights by focusing on the competencies manifested by efficient teams in adapting to stress. To this extent, a survey of how teams adapt their decision-making strategies, cooperation patterns and team structure has provided a good basis for proposing design principles for collaborative IDAs. The article concludes with some challenges for further developments in information technology and research needs in the area of teamwork under stress.

A framework for the analysis of cognitive reliability in complex systems: a recovery centred approach

Abstract Managing complex industrial systems requires reliable performance of cognitive tasks undertaken by operating crews. The infrequent practice of cognitive skills and the reliance on operator performance for novel situations raised cognitive reliability into an urgent and essential aspect in system design and risk analysis. The aim of this article is to contribute to the development of methods for the analysis of cognitive tasks in complex man-machine interactions. A practical framework is proposed for analysing cognitive errors and enhancing error recovery through interface design. Cognitive errors are viewed as failures in problem solving which are difficult to recover under the task constrains imposed by complex systems. In this sense, the interaction between context and cognition, on the one hand, and the process of error recovery, on the other hand, become the focal points of the proposed framework which is illustrated in an analysis of a simulated emergency.

A user-centred design approach for introducing computer-based process information systems

There has been an increasing tendency to use computer-based process information systems as the main interface through which operators interact with complex industrial systems. Although the new technology has produced greater hardware reliability and maintainability, the corresponding potential benefits for operability have not always been achieved. Automation has introduced new forms of design and operating errors. One of the major reasons for this problem has been the lack of human factors advice and user participation early in the design process. This paper discusses a user-centred design approach to increase operability and user acceptance of new technologies and working practices. Application of this approach in the context of a chemical plant indicates its promise, but also highlights the difficulties involved in gaining user participation and management commitment.

A comparison of accident analysis techniques for safety-critical man}machine systems

Abstract The complexity of modern industrial systems has prompted the development of accident analysis techniques focusing on specialised aspects of the system. Although it is difficult to find a single technique that would integrate the different types of analysis (e.g. event analysis, human error analysis, and causal factors analysis), accident analysis techniques should provide appropriate input to others investigating complementary aspects of the system. To fulfil this requirement, this article proposes a taxonomy of criteria for the assessment and revision of system engineering techniques that have been applied to accident analysis. The proposed criteria are illustrated in the context of three techniques, i.e. fault trees, sequentially Timed Events Plotting, and Petri Nets. The Piper Alpha incident has been selected as a case study to illustrate the strengths and weaknesses of the three accident analysis techniques. Extensions of the notation of these techniques are suggested in order to generate appropriate information for the analysis of human errors, error recovery paths and causal factors at the workplace and organisational levels. Relevance to industry Accident analysis techniques are essential in learning lessons and preventing similar unfortunate events in future. Advances in human error research provide useful opportunities for improving the effectiveness and usability of these techniques. A set of assessment criteria are proposed to provide a basis for further developments in accident analysis techniques.

Managing emergencies and abnormal situations in air traffic control (part II): Teamwork strategies

Team performance has been studied in many safety-critical organizations including aviation, nuclear power plant, offshore oil platforms and health organizations. This study looks into teamwork strategies that air traffic controllers employ to manage emergencies and abnormal situations. Two field studies were carried out in the form of observations of simulator training in emergency and unusual scenarios of novices and experienced controllers. Teamwork strategies covered aspects of team orientation and coordination, information exchange, change management and error handling. Several performance metrics were used to rate the efficiency of teamwork and test the construct validity of a prototype model of teamwork. This is a companion study to an earlier investigation of taskwork strategies in the same field (part I) and contributes to the development of a generic model for Taskwork and Teamwork strategies in Emergencies in Air traffic Management (T(2)EAM). Suggestions are made on how to use T(2)EAM to develop training programs, assess team performance and improve mishap investigations.

Training Effective Human Performance in the Management of Stressful Emergencies

Abstract: Emergency situations in industry occur suddenly and often unexpectedly; operators must make critical decisions under stress, and the consequences of errors can be immediate and catastrophic. Training effective performance under stress becomes an important aspect in the management of emergencies. This article proposes a taxonomy of cognitive strategies that enable operators to regulate their thinking and adapt decisions to changes in the demands of the situation. Cognitive strategies, such as, tolerating uncertainty, managing workload, planning for contingencies, and self-monitoring, provide the content of training emergency response. Stress, however, interferes with the learning of strategies, which presents a challenge to the design of training methods. Exposure to stress during training, degree of task decomposition, guidance, contextual variety and feedback are some of the training methods explored to facilitate the acquisition and transfer of cognitive strategies. Diversions from the traditional systems approach to training are pointed out and areas for further training research are identified.

A compound methodology to assess the impact of human and organizational factors impact on the risk level of hazardous industrial plants

Abstract This paper presents a compound methodology devised to relate Human and Organizational Factors (HOFs) to operators’ response time in critical operations within hazardous industrial plants. The methodology has been based on a sensitivity analysis of the nine “families” of the Common Performance Conditions (CPCs), as defined in the CREAM technique, in order to verify and rank their influence on the operators’ response time. To prove the methodology, a series of pilot experiments have been designed and performed so that human response is evaluated in a Virtual Environment (VE) reproducing the control room and a specific plant section. This environment enables the analyst controlling the simulation to perform the sensitivity analysis acting through a supervisory station and manipulating the control functions in order to vary each CPC rate around its nominal value. Experiments were run with the variation of one CPC at a time aiming at the detection and containment operation of a gas leakage in a pressure-reduction NG terminal. The whole case study has been run within the framework of the VIRTHUALIS EU project.

A Petri Net-based approach for ergonomic task analysis and modeling with emphasis on adaptation to system changes

Task analysis has been extensively used in industrial ergonomics in order to identify system demands and operator plans for achieving goals and coping with high workload. On the other hand, computer modeling has been used for simulating human-machine interactions under a range of conditions, such as changes in task allocation, team structure, operating procedures and system events. To integrate task analysis and computer modeling, a new technique is proposed that utilizes Coloured Petri Nets. The proposed technique has been developed on the basis of 12 requirements reflecting aspects of task representation, control and decision making, and usability. A Petri Net notation of tasks and a classification of Petri Net-based plans are first introduced. This article is mainly concerned with the development of routines for making task sequences and plans adaptable to system changes that could give rise to task interruptions, changes in goal priorities, changes in task allocation, high workload and human errors. An evaluation follows on the basis of the specified requirements for task analysis and task modeling. Relevance for the industry: Task analysis and task modeling are important for matching systems demands to operator capabilities. New computer modeling approaches, including Petri Nets, can simulate human-machine interactions under a range of conditions, such as technology innovations, changes in team structure, different allocation of tasks, and high workload.